Thomas Gale Moore
Senior Fellow
Hoover Institution
Stanford University
On May 21, twenty-one scientists sent a letter to President Clinton warning him that climate change would threaten biodiversity. They asserted that "climate change, in combination with existing anthropogenic habitat disruption and loss, could lead to steep declines in worldwide biodiversity." According to the group the speed of climate change would strongly affect the ability of species to adapt.
Current evidence suggests the opposite. Several scientists have recently reported an increase from 1981 to 1991 in plant growth in the northern high latitudes. More vigorous plant development, while possibly choking out a few species, provides a more plentiful habitat for animals. Similar reports have originated in Australia where researchers have found that warmer weather, more rainfall, and perhaps greater CO2 have led to bumper crops. The IPCC has postponed their predicted warming of 2.5 degrees from 2040 to 2100, indicating that climate change will be more gradual than believed previously. The evidence of greater fauna growth, together with the lengthening of the period of any warming suggests that fears of major species extinction are overblown.
Even though no one knows how many different species exist, many environmentalists claim that more species are going extinct than ever before. Paleontologists estimate, however, that roughly 99 percent of all species that have ever existed became extinct before humans invented agriculture. Nevertheless, most people feel it would be a tragedy to lose any existing varieties of animals and plants, with the possible exception of cockroaches, poison ivy, or rats.
In fact, most plants and animals can and do adjust to changes in the environment, sometimes with human help. Plants are probably at little risk in a higher CO2 world. Although the temperature is likely to rise, an environment richer in carbon dioxide is likely to stimulate growth. Moreover, higher CO2 levels would induce a more efficient use of water and make them more drought resistant. In addition, most models suggest an increase in rainfall worldwide.
If the warms slowly as expected, almost all mammals could migrate to a suitable climate. Ocean fishes need not fear climate change; at worst they might have to swim farther north. It is clear that although many species could adjust, not all would necessarily survive.
Measuring the value of biodiversity objectively is probably impossible. Many advocates of protecting species, such as the Union of Concerned Scientists and the 21 ecologists who authored the letter to the President, have argued that a major cost of any loss would come from the reduction in the genetic pool of untested plants that could in the future prove great benefit to mankind. Within that huge variety of DNA might lie cures for cancer, heart disease or more exotic ills. Although the number of species on the globe is unknowable, it is certainly large and has been estimated to be at least 10 million: scientists have identified about 1.4 million, about half of which are insects. Plants constitute about 250,000 different species from which drug companies hope to find new compounds.
Pharmaceutical companies have already spent significant sums investigating naturally occurring chemicals and hormones for possible health benefits. The United States has signed, but not ratified, the Biodiversity Convention, prepared for the United Nations Rio meeting in 1992. That agreement commits the signatories to respect the sovereignty and property rights of local governments over any genetic resources or compounds discovered on their lands. Conforming to this mandate, Merck and Company, for example, has signed an agreement with Costa Rica for a payment of $1 million and substantial royalties for any product discovered or developed from indigenous plants or animals. Other companies and countries are negotiating similar agreements.
Being skeptical about the vital importance of maintaining all species is the equivalent of being against motherhood, so one is reluctant to question the value of species diversity. Nevertheless, the value of any species, at least as a potential pharmaceutical, is probably very low. Among plants, there is considerable duplication in the production of chemical substances. Many creatures and plants have similar needs and consequently manufacture comparable compounds. The number of other plants or animals that produce like chemical affects the value of any one species. If many varieties of plants produce the same compound, the importance of any one kind is minimal. On the other hand, if very few code for therapeutic chemicals, the cost of discovery becomes excessive and the prediscovery value of any single species is negligible. If the species is found over a wide range, its value in any one area will be limited.
A new substance's contribution towards more effective medical treatment determines its ultimate value. Even if a plant variety is unique it may still provide no additional benefits over substances already known. In addition, alternative drugs may be equally effective in dealing with medical problems. Finally, synthetic drugs based on nonorganic chemicals can often be just as effective.
To find, develop, and test new chemical compounds is costly and time consuming. Typically it takes more than 10 years from the time of the discovery of a potentially valuable species until a new pharmaceutical substance is ready for sale. Over recent decades, drug companies have developed annually only a handful of new therapeutic drugs; the FDA approves only about 30 new substances a year of which perhaps 10 are derived from plants.
Making some reasonable assumptions about earnings and the probability of finding a useful species, the economists David Simpson, Roger Sedjo, and John Reid of the Resources for the Future, who examine the value of species for this purpose, conclude that AT MOST a species might, for pharmaceutical purposes, be worth $10,000. Under reasonable but less advantageous assumptions, its value could shrink to pennies. They calculate that an acre of the richest land with the greatest diversity (western Ecuador) would have a maximum value of only $8.00. Other less species-intense areas are virtually worthless from the point of view of providing potential new drugs.
The Greek chorus of doomsayers grossly overstates the value of biodiversity. Their exaggerated veneration of each and every species leads to mistaken policy and needless expense.
References:
R. David Simpson, Roger A. Sedjo, and John W. Reid. "Valuing Biodiversity for Use in Pharmacveutical Research" Journal of Political Economy, vol 104(1) (February 1996).
R. B. Myneni, C. D. Keeling, C.J. Tucker, G. Asrar, and R.R. Nemani. "Increased Plant Growth in the Northern High Latitudes from 1981 to 1991," Nature, vol 386 (17 April 1997).
Ecologists' Statement on the Consequences of Rapid Climatic Change, letter to President Bill Clinton, May 21, 1997.
Neville Nicholls, "Increased Australian wheat yield due to recent climate trends," Nature vol 387 (29 May 1997).